Ch13 The Theory of Evolution Study Guide
Vocabulary Words
Adaptation: a feature that has become common in a population because it provides a selective
advantage
Reproductive isolation: the condition in which two populations of the same species do not breed with
another because of their geographic separation
Punctuated equilibrium: periods of rapid change in species separated by long periods of little or no
change
Homologous structures: similar anatomical arrangements of body parts of organisms indicating a shared
common ancestor
Tuberculosis: a disease becoming difficult to treat because of the evolution of antibiotic resistance in
the infecting bacteria
Paleontologist: uses radiometric dating to determine the age of fossils
Mutations: a change in DNA that is one source of new variations for natural selection to act upon
Concepts to Know
On the Galapagos Islands, the numbers of finches with different beak shapes are changed by natural
selection in response to the available food supply.
An example of natural selection in an observable time frame is antibiotic resistance in bacteria.
In any population, there is an array of individuals that differ slightly from one another, this statement
best defines the concept of genetic variation.
One mechanism for reproductive isolation is geographic isolation.
The final step of speciation is reproductive isolation.
The characteristics of the individuals best suited to a particular environment tend to increase in a
population over time.
The fossil record seems to provide evidence for intermediate forms punctuated equilibrium, and natural
selection.
Species may have changed over time, and the genes that determine those species have changed as well.
Fossils have been found that provide a link in the evolution of whales from four-legged animals.
Subspecies can interbreed, but they are genetically different.
Darwin developed the theory of evolution by natural selection from Malthus’s principles of population,
the observations he made during the voyage of the Beagle, and his experience in breeding domestic
animals.
In South America, Darwin found fossils of armadillos that were similar to the armadillos living there.
There is clear evidence from fossils and other sources that the species now on Earth have evolved from
ancestral species that are extinct.
The forelimbs of vertebrates contain the same kinds of bones.
The part of Lamarck’s hypothesis of evolution that proved to be correct was that evolution is linked to
an organism’s environmental conditions.
Essays
What role does the environment play in natural selection? According to Darwin’s theory, those
organisms with traits that are best suited to the environment are more likely to survive and successfully
reproduce than those that do not have such traits.
Explain what comparing a human hemoglobin protein with the same hemoglobin protein of other
species can tell about evolution. Species that share a common ancestor recently, such as humans and
gorillas, have few amino acid sequence differences. Species that shared an ancestor in the distant past,
such as gorillas and frogs, will have many amino acid sequence differences.
Explain what Darwin meant when he referred to “the preservation of favorable variations” as natural
selection. Individuals having any slight advantage over others would have the best chance of surviving
and reproducing. Any variation that decreases the likelihood of reproducing would be destroyed. Thus,
the favorable variations would be preserved.